Let us know. Mine did come with a washer but there was no sealant. Don't always have to call your local dealer. I have called dealers all over the country when researching an answer.

 

Are you guys testing in the reservoir or the radiator?

 

Yes, test in the resovoir nor the radiator. Negative lead to positive battery terminal and positive in coolant. I know, sounds odd but those are the instructions. Try moving it around in the tank to see if the readings change much.

 

thought the video said don't go anywhere near the positive battery terminal. I didn't---one lead to the neg terminal, one lead to the coolant in the radiator.

here's my results:

05 LS--engine off: .2
05 LX470: off: .01; on: .12 drifting down to .05
08 Sienna: off: .15; on: .2
08 G37: off: .01; on: .04

kind of as I suspected. None of my vehicles exceeded the .3 but am still going to replace the coolant quite soon in the LS and Sienna.

Would you use this test as the primary determinant in whether to replace your coolant?

 

Tested mine this am. 2006 LS430 OEM factory fill coolant, 73k miles. Measured with test probe in overflow tank was .13, probe directly into radiator coolant tested as .18.

I am going to do TB/WP change next summer at apprx 83 k miles (and 11 years) and I'll ask them to insure all coolant is drained with that job.

 

You can actually use the positive or negative lead it does not matter. You just need to have one lead in the other lead in the reservoir tank. Sorry, I did mean negative terminal to be safer but both work.

Testing with the car off checks for the chemical breakdown of the fluid. Testing with the vehicle on is mainly used for looking for stray voltage from a bad ground. Both are good to do. The 2nd is more damaging but the presence of the voltage is not a good thing for health of the cooling system.

.3 is the general cut off point to go ahead and flush if you are reading this or more with the engine off. Again, two types of test. Chemical electrolysis and electrical eclectroysis

 

hey jabberwock...did i read this right...the coolant in your system has never been changed? and it still is only reading .13? if so, it kind of begs the question how old does the coolant have to get before it exceeds the .3. Or what conditions have to occur before you exceed the .3. Another way of looking at it, if you're really running the original coolant, then a limit of .3 would seem to be way too high....no way 9 yr old coolant can be good in the system.

 

Hey LAV......Lexus dealer got back to me...they said the temp sensor is supposed to be used with a gasket and that their techs install it dry...no sealant. He is sending me gasket ( or washer ) in the mail. Just fyi

 

Oh nice, that is good to know. Some sensors use the threads as a ground. This is most likely why they don't use any sealant. Glad I got that right...

 

Update............well the dealer I purchased the coolant temp sensor from also shipped me the washer / gasket......and I installed the part tonight along with a fresh OEM air filter. Pretty straight forward job.....of course I made it last longer then necessary.....and I removed all black plastic...black box....air intake etc. I just wanted an easy clear shot at the part. I was able to pinch and remove clip....then with the proper socket I easily removed the sensor....to my surprise some coolant looked like it was gunna bubble out......I put a towel in place and got ready for a quick part swap...but in the end the coolant was not a factor. I snugged her back down and took a test drive without the engine cover on so I could check for leaks........returned to my garage.....all good......put her back together and tucked her away in the garage.
Temp gauge needle stayed in same place and performance was the same. I am glad I did the job.....another DIY job in the books.....

Thanks to LAV for the info and heads up.

 

Nice work. I would do a soft reset and see if you notice improved mileage.

 

roger that......was the soft reset just removing the neg for a few minutes then re install?

 

Yes, but literally it just needs to be for 10 seconds.

 

rog....will do.....I am sure the new plugs will give me a little boost as well......the best my car has ever done is 21mpg........but I always goose it on the highway just for fun...and that throws my average off.
How often does the car update the mpg......? and how do I look up voltage on my nav screen?

 

I'm 95% sure the coolant is the OEM factory fill although I did buy it used with 13 k miles on it. Not sure any of this matters in terms of coolant, the car has always be garaged, drive 7-8k miles a year, see nothing in the way of snow/ice, driven pretty gently. I have asked the Lexus techs to check it a couple of times when I am in for State inspections, they tell me it is fine and to wait till I do the WP/TB next year. Coolant itself in terms of appearance is nice and clear with pink color.

The car has been bulletproof so far - I'm actually still running the original factory Panasonic battery - 10 years old now and instantly starts right up hot or cold.